public class HashBuck2<K,V> {
    static class Node<K,V>{
        public K key;
        public V value;
        public Node<K,V> next;
        public Node(K key, V value) {
            this.key = key;
            this.value = value;
        }
    }
    public Node<K,V>[] array = (Node<K, V>[]) new Node[10];
    public int usedSize;
    public static final double LOAD_FACTOR = 0.75f;

    public void put(K key,V value){
        int hash = key.hashCode();
        int index = hash % array.length;
        Node<K,V> cur = array[index];
        while(cur!=null){
            if(cur.key.equals(key)){
                cur.value = value;
                return;
            }
            cur = cur.next;
        }
        Node<K,V> node = new Node<>(key, value);
        node.next = array[index];
        array[index] = node;
        usedSize++;
        if(calculateLoadFactor()>=LOAD_FACTOR){
            //扩容
            resize();
        }

    }
    //扩容
    private void resize() {
        Node<K,V>[] newArray =(Node<K, V>[]) new Node[2 * array.length];
        for (int i = 0; i < array.length; i++) {
            Node<K,V> cur = array[i];
            while (cur!=null){
                Node<K,V> curNext = cur.next;
                int hash = cur.key.hashCode();
                int index = hash % newArray.length;  //找到了在新的数组的位置
                cur.next = newArray[index];
                newArray[index] = cur;
                cur = curNext;
            }
        }
        array = newArray;
    }
    public double calculateLoadFactor(){
        return usedSize*1.0/array.length;
    }

    public V get(K key){
        int hash = key.hashCode();
        int index = hash % array.length;
        Node<K,V> cur = array[index];
        while(cur!=null){
            if(cur.key.equals(key)){
                return cur.value;
            }
            cur = cur.next;
        }
        return null;
    }

}
